5-Hydroxytryptophan (5-HTP) is a natural non-proteinogenic amino acid that serves as a direct biosynthetic precursor to the neurotransmitter serotonin. Deficient serotonin in the central nervous system (CNS) is thought to be an important physiological factor for depression. 5-HTP has been shown to be effective for the treatment of a variety of conditions, including depression, insomnia, chronic headaches and binge eating associated with obesity. At the same time, it has relatively few side effects. The therapeutic efficacy of 5-HTP is due to its ability to enhance the synthesis of serotonin in the brain. 5-HTP is well absorbed from an oral dose and can easily cross the blood-brain barrier (Birdsall, 1998 Altern. Med. Rev. 3:271-280). In most European countries, 5-HTP is a commonly prescribed drug for multiple treatment purposes; while in North America market it is sold as an “over-the-counter” dietary supplement.
Currently, 5-HTP is obtained through extraction from the seeds of Griffonia simplicifolia, a woody climbing shrub grown in Africa. The season- and region-dependent supply of the raw materials has been largely limiting its cost-effective production and broad clinical applications. In addition, Griffonia derived 5-HTP has been contaminated with a compound called Peak X, leading to the USDA briefly removing the supplement from shelves in the US. The current bulk wholesale price for 5-HTP ranges from 400 to 1000 USD/kg. Yet despite the current high production cost and limited supply, the global market of 5-HTP is still about 50,000 kg (bulk value 20-50 million dollars).